

MUCIN OF FIBROUS CONNECTIVE TISSUE. 43 



the carbohydrate radicle is subject to variation, and it is easy 

 to conceive of differences in the nature and properties of the 

 mucins dependent upon variations in the amount and character 

 of both the carbohydrate and proteid groups. The ready 

 formation of acid-albumin, or syntonin, albumoses, and peptone 

 when mucins are decomposed by the action of superheated 

 water or boiling dilute acids, affords ample evidence of the 

 presence of true proteid radicles in the bodies of this class, 

 although we do not know definitely the exact nature of the 

 proteid groups present in the original molecule. On the other 

 hand, the simultaneous formation of reducing bodies whenever 

 mucins are broken down by the action of dilute acids, and the 

 separation of a dextrin-like body (the animal gum of Land- 

 wehr *) by cleavage with superheated water, clearly indicate 

 the existence of some form of carbohydrate matter in the 

 mucin molecule. 



Of the true mucins present in the tissues of the higher 

 animals, the mucin of the submaxillary gland and the corre- 

 sponding body present in or between the fibres of ordinary 

 connective tissue are the most important from a physiological 

 standpoint. The former is a product of the metabolic activity 

 of secretory cells which are among the most active of the 

 secreting cells of the body, while the latter is a product of a 

 tissue whose activity is certainly of a low order. That these 

 two mucins, though closely related, are unlike, is clearly 

 indicated by their divergence in chemical composition as well 

 as by their general reactions and properties. 



Loebisch,f whose careful study of the mucin from tendons 

 constitutes the chief source of our knowledge regarding the 

 chemical composition of this body, ascribes to tendon-mucin 

 the formula CieoHWN^SiOso, with a molecular weight of 3,936. 

 Such a formula calls for the presence of 0.81 per cent of 

 sulphur, and this amount was found by Loebisch in the three 

 preparations of mucin from ox tendons analyzed by him. In 



* Zeitschr. f. physiol. Chem., Band viii and is. Also Pfliiger's Archiy f 

 Physiol., Band xxxix and xl. 



t Zeitschr. f. physiol. Chem., Band x, p. 40. 



